Design of laying nests in furnished cages: influence of nesting material, nest box position and seclusion

(1) Preferences for three nesting materials and nest box positions were investigated simultaneously in two trials using a furnished cage: one with 18 individual laying hens and one with 18 groups of 5 hens. Following a habituation period in pre-test cages, every hen or group of hens was tested for 2 d: once without and once with plastic flaps at the entrance of the nest boxes. (2) Hens preferred peat and artificial turf to coated wire mesh for egg laying. (3) One nest box position was clearly preferred to both other nest boxes. The hens' choice of nest box position was influenced by the pre-test cage in which they had been habituated. (4) The presence of plastic flaps at the entrance of the nest boxes had no influence on the proportion of eggs laid on the different nesting materials or on the proportion of floor eggs. (5) Individual and group testing resulted in the same overall results despite the presence of a distinct group effect.     

Design of nest boxes for laying cages

1. ISA Brown hens were housed in groups of 4 in cages with different designs of nest boxes provided, to determine the effects of nest box design and management on their use and on the pre‐laying behaviour shown by the birds.

2. There were 5 treatments: control (C); a wire‐floored nest box attached to the back of the cage (W); a nest box containing a fibreglass rollaway hollow (N); two rollaway nest boxes (T); a rollaway nest box, protected by a partition from the main part of the cage (P).

3. The holes in the rollaway nests in treatment N, T and P were shut initially, but the proportion of eggs laid in these nests only reached 50%. This proportion rose to over 80% when wood shavings were added daily, but fell to below 30% when rollaway holes were opened. These rollaway hollows are apparently not suitable for use in laying cages.

4. Use of nest boxes in treatment W varied between 60 and 80%. However, when pre‐laying behaviour was recorded (in 19 hens) two birds which laid in the nest boxes nevertheless showed abnormal behaviour.

5. Individual hens had on average 29 to 60% of their pre‐laying behaviour overlapped by that of others in the cage. Nesting space for at least two birds is probably necessary in a cage for 4 birds. However, in treatment T pre‐laying behaviour was disturbed by hens moving between the two boxes. This would be avoided by provision of one box big enough for two hens.

6. Soiling of hollows resulted in dirty eggs and suggested that nest boxes for laying cages may have to be provided with doors to prevent hens from roosting in them.     

Comparison of Preferences of Farmed Silver and Blue Foxes for Cages with and without a Nest Box

Abstract

The preferences of juvenile farmed silver foxes (n = 14) and blue foxes (n = 12) for an empty cage (105L × 115W × 70H cm) and a cage of equal size with a wooden nest box were assessed in an 11-day preference test. The silver foxes spent a higher percentage of their time (86 ± 8%) in the nest box cage than the blue foxes (66 ± 21%). The silver foxes, but not the blue foxes, had a strong preference for the nest box roof as a resting site (44% of total daily time). Assuming that greater use indicates a greater need, silver foxes may benefit more from the nest boxes than blue foxes.     

Frustrated nesting behaviour: relation to extra-cuticular shell calcium and bone strength in White Leghorn hens

1. The inability of hens to express normal nesting behaviour in battery cages results in frustration, manifesting itself as stereotyped pacing. Frustration can cause hens to retain their eggs beyond the expected time of lay, resulting in an extra-cuticular layer of calcium on eggshells. 2. This study investigated whether frustrated nesting behaviour caused extra-cuticular calcification of eggshells and whether this loss of non-structural calcium to eggshells may have subsequently contributed to weak bones in spent hens. 3. One hundred and twenty hens were assigned to one of three treatments: NB (hens given nest boxes in their cages), NN (no nest box) and R (access to nest box periodically restricted). 4. NB hens spent the least amount of time pacing in the hour before oviposition. NN and R hens spent similar amounts of time pacing. 5. Contrary to expectation, eggshells from hens under different treatments yielded the same amount of extra-cuticular calcium. Similarly tibia strength did not significantly differ among treatments.     

Behaviour of laying hens in cages with nest sites

1. Behavior of ISA Brown hens was compared in cages with and without nest sites provided, to determine the characteristics necessary for such nest sites and whether part of the existing cage area could be modified to form an acceptable nest file. 2. There were 5 treatments: control (C); a wooden surround in one rear corner of the cage (S); a fiberglass rollaway hollow in one rear corner of the cage (H); a hollow and a surround (H/S); a nest box attached to the back of the cage, containing a hollow (N). 3. Use of rollaway hollows was limited, unless they were blocked and wood shavings were added, when 55 to 60% of eggs were laid in them. There were also problems with soiling of hollows. 4. When hollows were blocked, most hens used them in treatments H/S and N, suggesting that substrate and surroundings both contributed to acceptability of nest sites. 5. Pre-laying behaviour in sites within the cage was disturbed and sometimes abnormal. In addition, these sites were not used for other activities, thus limiting the space available. 6. For pre-laying behaviour to be expressed satisfactorily in cages, an additional nesting area, such as a nest box or boxes, is probably necessary.     

Effect of Inside-cage and Outside-cage Environment on Behaviour Test Performance of Blue Foxes (Alopex lagopus)

Abstract

In-cage reaction tests, the open field test and daily activity in the home cage were used to assess the effect of the internal design and location of cages on the behaviour of juvenile blue foxes (Alopex lagopus) during the growing season. The inclusion of nest boxes or resting platforms affected the behaviour of farmed blue foxes, but to a lesser extent than did the location of the animal in the cage row, i.e. the environment outside the cage itself. This study demonstrated that the actual environment in which the farm foxes live may be far larger than the cage interior itself, and that attempts to improve housing design should take into consideration the environment outside the cage to a greater extent than has heretofore been the case.     

Relation between social order and use of resources in small and large furnished cages for laying hens

1. The objective was to determine the relation between social rank and use of resources in a small furnished cage with sufficient resources per hen (SF) and a commercial large one with less adequate allowance of facilities per hen (LF). 2. Ninety-two cross layers were used. At the age of 16 weeks, the hens were divided at random into two groups. There were 4 furnished cages with 5 birds per cage and 4 large furnished cages with 18 birds per cage. The dominance hierarchy was determined, in which highest, medium and lowest ranking hens in each cage were identified. Behaviour, use of facilities and physical conditions of these hens were measured (one in each rank category in SF, two in each in LF). 3. Dustbathing and litter scratching were more frequent in the high ranking hens than the medium and low ranked hens in LF, while no significant difference was found between them in SF. 4. No significant difference between SF and LF was found in use of nest boxes. However, pre-laying sitting tended to be less frequent in low ranking than medium and high ranking hens in LF (Social order x Cage design). In the nest box most of time was spent in pre-laying sitting by SF hens, LF high and medium ranked hens (average 94.9%). However, LF low ranking hens spent their time escaping (33.1%), pre-laying sitting (27.7%) standing (25.7%) and moving (13.5%) in the nest. 5. In the large furnished cages with less facilities per hen, high ranking hens may be expected to have priority using the dust bath. In contrast, low ranking hens rarely performed nesting behaviour fully, and spend more time using the nest box as a refuge than for laying.     

Individual variation in prelaying behaviour and the incidence of floor eggs

1. Floor eggs are a problem in non‐cage systems for laying hens, as they require secondary egg collecting. Failure to lay in a well‐defined nest site may also be a welfare problem for the hens, but only if their nesting motivation has been thwarted.

2. We investigated the relationships between a hen's prelaying behaviour and its tendency to lay on the floor by recording the behaviour of 20 hens housed individually in wire cages with single littered nest boxes.

3. Most floor eggs (80%) were laid by the same 6 hens. These 6 “floor‐layers” performed more nest seeking behaviour, less nest‐building behaviour and less sitting prior to oviposition than the 14 hens that consistently laid in nest boxes.

4. The incidence of floor eggs declined with age. Both nest and floor laying hens performed less nest seeking behaviour with age. Floor layers, however, increased their performance of nesting behaviour, whilst nest layers performed less nesting behaviour with age.

5. Floor laying hens behaved as if they found the nest box less attractive than nest‐laying hens; perhaps because they had lower nesting motivation, or perhaps because their nesting motivation was as high, but they less readily perceived the nest box as an appropriate nest site.     

Nesting and dust bathing by hens in cages: Matching and mis‐matching between behaviour and environment

1. Medium hybrid hens were housed as groups of 4 at 18 weeks of age in cages of 4 different types: control battery cages allowing 675 cm2/bird; similar cages with a rear‐mounted dust bath, 290×345×240 mm, containing sand (D); cages with a rear‐mounted nest box of the same size, containing wood shavings (N); cages with both (DN). In half the experimental cages access to nests was restricted to the morning and access to baths was restricted to the afternoon, by automatic sliding doors.

2. During the first 24 weeks of lay about 95% of eggs were laid in nest boxes in treatments N and DN. Slightly fewer were laid in boxes where doors were present. Over 90% were laid in dust baths in D cages without doors and 67% with doors, which birds learned to open. Prelaying behaviour was least disturbed in nest boxes, most disturbed on the floor and intermediate in dust baths.

3. Fully developed dust bathing occurred in D and DN as bouts lasting 5 to 10 minutes; its incidence, surprisingly, was greater when doors were present and greater still when nest boxes were present, even though it was not performed in them. It was also performed by some hens in nest boxes in N (without doors). In N with doors and in control cages, dust bathing occurred on the bare floor in truncated form, as serial bouts each lasting only about 10 s. This truncated dust bathing was also occasionally observed in D and DN.

4. Plumage, foot and claw damage were less in hens from modified cages than from controls. Egg production was very good in all treatments but more eggs from control cages were downgraded because they were dirty or cracked.

5. When a choice was available birds generally partitioned their behaviour appropriately between nest box and dust bath. In N and DN virtually all prelaying and nesting behaviour took place in the nest boxes. Matching between dust bathing and the environment was less close; the reasons for its relatively low incidence and occurrence in truncated form outside dust baths remain to be established.     

Egg shell colour is affected by laying cage design

1. When laying hens are stressed some retain their eggs in the shell gland beyond the normal time of laying and this can result in the deposition of extra-cuticular calcium which makes brown eggs appear paler. 2. Three different types of enriched modified cage were compared: the location where eggs were laid was recorded and shell colour was measured using a reflectometer. 3. In 2 types of cage with enclosed nest boxes more eggs (80%) were laid in the nests than in a design with nest hollows in the open part of the cage (41%). 4. The eggs from the cages with enclosed nests were darker (had less extraneous calcium) than those with open nest hollows. This implies that in the designs with nest boxes fewer eggs had been retained and the hens may have been less stressed. 5. The results support previous evidence that to reduce stress and improve welfare it is desirable to provide enclosed nest sites for caged laying hens.     

Swimming Activity of Farm Mink (Mustela vison) and its Relation to Stereotypies

Eighty farm mink were used to investigate whether access to swimming water and:or difference in cage size led to a difference in the level of stereotypies. Half of the animals grew up with free access to swimming water, and the other half without. In addition, two different cage sizes were used. Over 2 weeks the animals were scanned a total of 141 times. Animals in small cages had a higher level of stereotypies and were more active than those in large cages. No difference between animals with swimming water and animals with an empty basin was detected. The level of activity was lowest in animals in large cages, although not significantly so when water was present. The results presented here do not offer any support for the claim that farm mink with access to swimming water have a lower level of stereotypies than mink with access to an empty basin. Whether swimming is a behavioural need in farm mink is still debatable.     

Evaluation of the effects of cage height and stocking density on the behaviour of laying hens in furnished cages

1. Limited information is available on how changes in horizontal and vertical space within enriched or furnished layer cages (as defined by Directive 1999/74/EC) influence hen behaviour. This study evaluated the effects of varying minimum cage heights and space allowances on the behaviour of laying hens housed in furnished cages. It was conducted on two flocks of medium brown hybrid hens housed in furnished cages with access to perches and nest boxes on a semi-commercial scale at ADAS Gleadthorpe. 2. Flock 1 consisted of two layer strains (ISA Brown and Babcock 380), housed at two minimum cage heights (38 and 45 cm) and 5 stocking densities between 609 and 870 cm2/bird, with 12 replicates of each of the 20 strain/cage height/stocking density treatment combinations. Stocking density was varied by varying the number of birds per cage from 10 to 7 in standard full-width cages or housing 7 hens in a narrower cage. As a consequence stocking density, group size and trough width per bird co-varied for 4 out of 5 stocking density treatments. 3. Behaviour of flock 1 was sampled at 33 to 36, 46 and 68 weeks of age. At each age one top-tier, one middle-tier and one bottom-tier cage was sampled for each treatment. 4. Few behavioural differences due to cage treatments were detected. Hens at 870 cm2 had shorter feeding bouts than hens at 609 and 762 cm2. Yawning was more common in the cages with greater cage height. 5. Video recordings of flock 1 examined cage height effects on hens' use of vertical space and provided additional data on stretching and self-maintenance activities. No differences in behaviour between 38 and 45 cm cages were found except that scratching head was more common in cages with greater cage height. 6. Flock 2 consisted of two layer strains (Shaver Brown and Hy-Line Brown), housed at 38 and 45 cm and 609, 762 and 1016 cm2/bird, with 18 replicates of each of the 12 strain/cage height/stocking density treatment combinations. Stocking density was varied by housing 10, 8 or 6 hens in standard full-width cages. Behaviour of flock 2 was sampled at 30, 48, 60 and 67 weeks from video recordings. Three cages per treatment from middle-tiers only were sampled at each age. 7. Hens housed at 609 cm2/hen had the longest mean feeding bout, greater than for hens at 762 cm2/hen but not hens at 1016 cm2/hen. More unsuccessful attempts to reach the feeder and sideways and backwards displacements from the feeder occurred at 762 and 609 cm2/hen than at 1016 cm2/hen. A maximum of 8 hens were observed feeding synchronously. 8. These results suggest that changes in horizontal and vertical space over the ranges we studied had little effect on behaviour other than feeding behaviour. Specifying a minimum useable trough space per hen, rather than calculating feeder space from total length of feeder per cage, irrespective of accessibility, might help avoid crowding at the feeder and associated disturbance of feeding bouts.     

Differences of behavior, use of resources and physical conditions between dominant and subordinate hens in furnished cages

The objective of the present study was to search for differences in the behavior, use of resources and the physical condition between dominant and subordinate birds in furnished cages. In total, 60 commercial White Leghorn layers were used. At the age of 54 weeks, these birds were divided into two groups. Each group consisted of six cages with four birds per cage and six cages with six birds per cage. The dominance hierarchy was measured, to identify the highest dominant bird and the lowest subordinate bird in the hierarchy of each furnished cage. Behavioral observations using scanning techniques at 10 min intervals were conducted on the birds at 57 and 67 weeks of age for 3 days, respectively. Their physical condition (bodyweight and claw length) was also measured. Dominant birds used the dust bath more (P < 0.1) and nest box less (P < 0.01) than subordinate birds did. The use of the nest box decreased for subordinate birds from 57 to 67 weeks of age (P < 0.05). The dominant birds performed aggression and exploring more frequently than the subordinate birds (P < 0.001 and P < 0.05, respectively). In the comfort behaviors, the dominant birds performed dust‐bathing, as well as the using the dust bath, more than subordinate birds did (P < 0.1). In their exploring behavior, including scratching and litter pecking, dominant birds performed both behaviors more frequently, as well as using the dust bath and dust‐bathing in it, than subordinate birds did (P < 0.1 and P < 0.05, respectively). Aggression decreased for dominant birds from 57 to 67 weeks of age. In contrast, eating (P < 0.1) as well as drinking (P < 0.1) and other comfort behaviors (P < 0.1) increased for subordinate birds from 57 to 67 weeks of age. There was no significant difference between dominant and subordinate birds in their physical conditions. In conclusion, dominant birds had priority to use the dust box compared with the subordinate birds in the furnished cages. Conversely, the subordinate birds stayed in the nest box more than the dominant birds did. In the furnished cages, equipping the nest box was important not only for the birds to perform nesting behavior, but also for the subordinate birds to use the facility as a refuge especially just after introduction to the cage.     

Development of furnished cages for laying hens

1. A 3-year trial was carried out of cages for laying hens, occupying a full laying house. The main cage designs used were 5000 cm2 in area, 50 cm high at the rear and furnished with nests and perches. F cages had a front rollaway nest at the side, lined with artificial turf. FD cages also had a dust bath containing sand over the nest. H cages had two nest hollows at the side, one in front of the other. They were compared with conventional cages 2500 cm2 in area and 38 cm high at the rear. 2. Cages were stocked with from 4 to 8 ISA Brown hens per cage, resulting in varied allowances of area, feeder and perch per bird. No birds were beak trimmed. In F and FD cages two further treatments were applied: nests and dust baths were sometimes fitted with gates to exclude birds from dust baths in the morning and from both at night; elevated food troughs, with a lip 33 cm above the cage floor, were compared with standard troughs. 3. Management of the house was generally highly successful, with temperature control achieved by ventilation. Egg production was above breeders' standards and not significantly affected by cage design. More eggs per bird were collected when there were fewer birds per cage but food consumption also then tended to be higher. 4. The number of downgraded eggs was variable, with some tendency for more in furnished cages. Eggs laid in dust baths were often downgraded. Those laid at the back of the cage were frequently dirty because of accumulation of droppings. H nests were unsuccessful, with less than 50% of eggs laid in the nest hollows. However, up to 93% of eggs were laid in front rollaways, and few of these were downgraded. 5. Feather and foot damage were generally less in furnished than in conventional cages, greater where there were more birds per cage. With an elevated food trough there was less feather damage but more overgrowth of claws. In year 2, mortality was greater in cages with more birds. 6. Pre-laying behaviour was mostly settled in front rollaway nests. Dust baths were used more for pecking and scratching than for dust bathing. Comfort behaviour was more frequent in furnished cages than conventional, although still not frequent. Locomotion was strongly affected by number of birds per cage or by space per bird, being reduced by crowding. Most birds perched at night except in one treatment providing only 10.7 cm perch per bird. 7. Behaviour was more unrestricted and varied, and physical condition was better, in furnished than in conventional cages. However, egg production will cost more in furnished cages, partly because more eggs are downgraded. Dust baths must be fitted with gates that the birds cannot open from outside, but gates for nest boxes were found unnecessary. If a low perch is fitted it must be far enough from the back of the cage for birds to walk there. 8. Where there was less space per bird (more birds per cage) than the requirements in the 1999 European Commission Directive on laying hens, there were: fewer eggs per hen, but still above the breeders' target; lower food consumption; more feather and foot damage, but less than in conventional cages; higher mortality in one trial out of three; less freedom of movement. However, the results were still very good even with 8 birds per cage, and support the principle that furnished cages provide an acceptable way of protecting the welfare of laying hens.     

Nesting,dust bathing and perching by laying hens in cages: Effects of design on behaviour and welfare

1. Laying hens (192 ISA Brown medium hybrids) were housed from 18 to 72 weeks as groups of 4 in conventional or experimental cages. The main area of all cages provided 675 cmVhen. All experimental cages had perches, dust baths and nest boxes, which were of three types: litter (L), artificial turf (A) or plastic rollaway (P). These facilities provided an additional 375 to 480 cm²/hen. The nest boxes and dust baths occupied either high or low positions. Behaviour, physical condition and production of the birds were regularly recorded.

2. Mortality was low (1.6% overall) and egg production very good in all treatments. The proportion of cracked and dirty eggs was slightly (but not significantly) higher in the experimental cages. In the experimental cages 90% of eggs were laid overall in the nest boxes and 3% in the dust baths. The proportion laid in the nest boxes was lower early in the laying cycle and increased with time, reaching 99% in A.

3. The facilities were heavily used. Birds spent about 25% of day time on the perches and 10–15% in or near the nest box and dust bath. At night, the majority of birds (90 to 94%) roosted on perches, but most of the remainder were on the lips of the nest box or dust bath, fouling the interiors.

4. Pre‐laying behaviour was much more settled in the experimental cages (45 min spent in the eventual laying position) than in the conventional ones (20 min) and total duration varied from 68 min in A to 87 min in P. The number of nest entries varied from 3.0 (A and P) to 4.3 (L); disturbance to sitting birds was correspondingly greater in L.

5. Dust bathing in the experimental cages generally took place during the afternoon in a single bout of about 5 min duration, whereas in the conventional cages it was brief and fragmented (3 bouts of 10 s each). The dust bath was also used for foraging behaviour (pecking and scratching). The treatments with small dust baths (A and P) caused problems for the birds.

6. Feather, foot and claw damage all tended to be less in the experimental than in the conventional cages, though only in the last case was the difference significant. Keel bone depressions appeared to be associated with perches; they were present in 43% of hens in the experimental cages but only 4% in conventional cages. There were no significant differences in body weight or in tibial or humerus strength between birds in the various treatments.

7. This study confirms that experimental cages with nest boxes, dust baths and perches offer appreciable benefits for welfare, with few production problems. The most successful treatment (A) could, with relatively minor modifications, form the basis of a practical design for large-scale commercial production.     

The Edinburgh modified gage for laying hens

1. Behaviour, production and welfare of ISA Brown medium hybrids were assessed in 2 trials (each from 20 to 44 weeks of age) of a novel design of cage for laying hens: the Edinburgh Modified Cage (EMC).

2. The EMC was 600 mm wide, 450 mm deep and 450 mm high at the rear; it had a softwood perch and at one side a 250 mm wide nest box (containing litter or artificial turf) with a dust bath direcdy above. It housed 4 birds and provided 675 cm^2/bird in the main cage with an additional 281 cm² /bird in the nest box. The nest box and dust bath had automatically controlled doors which were closed at night. There were 18 EMC; in the first trial these were compared with 6 control cages with perch but without next box or dust bath.

3. Hens spent 32 to 37% of day time on the perch, 5 to 7% in the dust bath and 5 to 6% in the nest. At night 92 to 98% roosted on the perch.

4. Initially only 55 to 70% of eggs were laid in the nest box partly because some eggs were laid before dawn. Once the door was retimed to open 3h before lights‐on the proportion rose to 91 to 96%. Very few eggs were laid in the dust bath. Pre‐laying behaviour lasted longer in treatments with nest boxes (55 to 76min) than in control cages (48min); disturbance was slight in all treatments, but lowest in control cages.

5. Dust baths were well used, with on average 61% of hens dust bathing during a 3‐h afternoon observation period compared with only 17% in control cages. Two birds could use the dust bath simultaneously.

6. It was concluded that although a number of minor design features still required attention the EMC has potential to reduce the disadvantages of conventional cages for welfare while retaining their advantages and has possible commercial application.     

Genetic parameters and effect of selection for body weight in lines of mink (Neovison vison) on ad libitum and restricted feeding

Abstract

Selection was performed for high November weight on ad libitum (AL) and restricted feeding (RF) in mink in two generations. A farm fed line (FF) was maintained as a control. The estimates of heritability for November weight were large (0.62, 0.52, and 0.73 in males and 0.68, 0.51, and 0.60 in females in the FF-, AL-, and RF-line). The results indicate that selection on AL feeding increased appetite and thereby improved feed conversion ratio while selection on RF improved feed utilization. Furthermore, the results suggest that selection for August weight produces lean mink while selection for November weight produces fat mink.     

Effects of Family Housing on Behaviour,Plasma Cortisol and Performance in Adult Female Mink (Mustela vison)

Various behavioural, physiological and production-related parameters were examined in 200 adult female pastel and pearl mink either family housed in three-room cages with no weaning or housed singly in one-room cages after normal weaning procedures. Scanning observations of behaviour and use of the cages were performed in the nursing period and several parameters related to reproduction were registered. The adult female mink were weighed when kits were 16 weeks old (September) and again at pelting time (November). Blood samples were collected from all adult female mink in September at which time the teat condition and fur damage were evaluated. After pelting, bite marks on the leather side of the skin were counted, fur damage was graded after severity and the fur size was measured. Some positive consequences of being family housed were revealed. The familyhoused adult female mink showed a lower level of stereotypes and a higher level of defensiveness and curiosity than the adult female mink in one-room cages during the nursing period. In September and November, family-housed adult females were heavier than singly housed adult females. However, most of the physiological or production-related parameters pointed in a negative direction for familyhoused adult female mink. Reproductive success was somewhat reduced, although not significantly. Plasma cortisol levels were elevated in September, indicating higher levels of stress in these females. They showed a generally poor teat condition in September, with a high proportion of swollen or bitten teats. A high proportion of these adult females showed fur damage in both September and November, and a high number of bite marks was found on the leather side of the skins of these females, indicating that family housing had a high cost for the adult female mink. In conclusion, there seem to be some benefits, at least on the behavioural level, in keeping adult female mink in three-room cages during the nursing period, but both physiological and production-related parameters indicated that the welfare of the adult female mink was threatened if she was continuously cohoused with her litter past the normal age of weaning.     

Perching behaviour and perch height preference of laying hens in furnished cages varying in height

1. The objective was to investigate the effect of cage height on perch height preference and perching behaviour in laying hens. Twelve groups of two hens and 12 groups of 14 hens were tested in furnished cages equipped with two wooden perches. These stepwise perches were designed such that hens could choose between 7 different heights (6, 11, 16, 21, 26, 31 and 36 cm). Day- and night-time perching behaviour was observed on 4 consecutive days with a different cage height each day: 150, 55, 50 and 45 cm. 2. Given that a minimum perch-roof distance of 19 to 24 cm was available, hens preferred to roost on the highest perches at night. 3. Lowering cage height not only forced hens to use lower perches, but also reduced time spent on the perches during the day (two-hen and 14-hen test) and night (14-hen test). Moreover, it affected daytime behavioural activities (more standing and less preening) on the perches in the two-hen tests (but not in the 14-hen tests). 4. During the day lower perches were used more for standing and walking, higher perches more for sitting and sleeping. This behavioural differentiation was most pronounced in the highest cages. 5. Perch preference and perching behaviour depend on both the floor-perch distance and the perch-roof distance. Higher cages provide more opportunity for higher perches (which hens prefer), for better three-dimensional spacing (and consequently reduced density at floor level) and for behavioural differentiation according to perch height.     

Bacterial eggshell contamination in conventional cages, furnished cages and aviary housing systems for laying hens

The influence of housing system on the initial bacterial contamination of the eggshell was studied. Two long-term experiments were performed. Bacterial eggshell contamination, as expressed by total count of aerobic and Gram-negative bacteria, was periodically analysed for eggs from a conventional cage, a furnished cage with nest boxes containing artificial turf or grids as nest-floor material and an aviary housing system. Results were log-transformed prior to statistical analyses. For both experiments no systematic differences were found between the conventional cage and furnished cage. The type of nest-floor material in the nest boxes of the furnished cages also did not systematically influence the bacterial contamination. A possible seasonal influence on contamination with a decrease in the winter period (up to > 0.5 log cfu/eggshell) of total count of aerobic and Gram-negative bacteria was observed in the first experiment. The contamination with total aerobic flora was higher (more than 1.0 log) on eggs from the aviary housing system compared to the conventional and the furnished cage systems. For Gram-negative bacteria this was not the case. During the entire period of both experiments, independent of housing system, shell contamination was not influenced by age of hens or period since placing the birds in the houses. For the total count of aerobic bacteria a restricted positive correlation (r2 = 0.66) was found between the concentration of total bacteria in the air of the poultry houses and initial shell contamination.